The long-term goal of the proposed research is to prevent the blindness due to glaucoma. The role played by the systemic blood pressure in glaucoma is not known. A systematic appraisal of the relationship of systemic blood pressure to the vulnerability of the optic disc in glaucoma is needed, and is the objective of the proposed research. We will produce a subhuman primate model of glaucoma and systemic hypertension (by laser photocoagulation of the anterior chamber trabecular meshwork and by aortic coarctation, respectively, and will then determine whether reducing pathologically elevated blood pressure increases the susceptability of the optic disc to damage by the elevated intraocular pressure. Since we cannot easily do visual field examinations in monkeys, alternate criteria of optic damage will be used. We have developed new techniques for measuring the circulation and topography of the optic disc and surrounding regions. Optic disc damage will be defined as a statistically significant and detrimental change in these parameters (e.g., increase cupping and/or delayed filling of the optic disc). A sufficient number of animals and an adequate follow-up will be used so that we may reliably estimate the probability that an individual with high blood pressure and elevated intraocular pressure will develop progressive optic disc damage when the blood pressure is lowered.